August 2020 Volume 2

FORGING RESEARCH

Additive Manufacturing Forging Die Fabrication By Dr. Prabir K. Chaudhury and Dekland D. H. Barnum

Additive Manufacturing (AM) or Direct Manufacturing, popularly known as 3D Printing, has become a leading-edge manufacturing technology. Today, metal AM is a reality, not only for prototype fabrication but for functional parts in all industrial sectors [1]. The potential for metal AM has led to heightened interests in all services of the Department of Defense (DOD) and enabled the implementation of several functional metal parts in weapons systems [2]. Civilian industries, specifically aerospace and medical implants manufacturing, have seen an accelerated effort in the implementation of metal AM functional parts. Most US casting foundries use AM technology to manufacture complex molds for various casting methods, and many cast parts are being converted to metal AM depending on the size and functional criticality. Forgings, on the other hand, cannot be replaced by metal AM because of their superior mechanical properties, functional criticality, and favorable production volumes. However, it is important for the forging industry to embrace metal AM in order to take advantage of this disrupting technology on its quest to reduce lead time and life-cycle cost in manufacturing forged products. This article reports such an effort under the Defense Logistics Agency (DLA)-funded Forging Defense Manufacturing Consortium (FDMC) program in collaboration with the Forging Industry Association (FIA). Background Procurement of forgings has been a very difficult issue for DLA in fulfilling its goal to support warfighters in a timely and economic manner. All services of the DOD use forgings for all weapons systems. The forgings are used exclusively for fatigue, fracture, and safety critical structural parts, and have the highest impact when a system fails due to unavailability of the forged products. Because of their unparalleled performance, procurement of metal forgings is extremely critical in supporting the warfighters in a timely manner. A recent Defense Technical Information Center (DTIC) report [3] examined which DLA-managed legacy parts are potential AM candidates and explained their selection criteria.This report revealed that out of 4.5millionDLA-managed class IX parts, over 1.7million parts are made from steel and aluminum alone, and approximately 140,000 parts can be manufactured by AMwith currently available AM materials. Most importantly, the lead time research revealed that for just one FSC code 1560, aircraft structural parts made from aluminum alloys and a designated critical flight/safety item costing between $100 and $1,000, the combined lead time is over 360 days. One of the major problems in procurement of the forgings remains two or three tiers below the direct suppliers of the forgings in the

supply chain. While forging is a best method of manufacturing robust and durable products, the required tooling to produce forgings drive the lead times and cost. 30 to 90 percent of forging cost and manufacturing lead time is associated with the forging die, depending on the quantity; the lower the quantity, the higher the influence of the die cost and lead time. Out of the several thousands of forgings procured by DLA annually, most are procured in quantities of less than 10, and therefore, new die manufacturing by conventional methods is time and cost prohibitive. Advancement of forging die manufacturing, therefore, is the key to reducing lead times and life-cycle costs of existing or new forgings. This FDMC project is aimed towards resolving some of the problems DLA has been facing for decades in the procurement of Forgings. Objectives The objective of the FDMC project, entitled AM Forging Die Fabrication, is to investigate the feasibility of metal AM (additive manufacturing) technologies and materials to fabricate forging dies. This project will investigate the following in this assessment: • Technology and Manufacturing Readiness Levels (TRL and MRL) for forging die fabrication by metal AM • Potential family of DLA forged parts and materials suitable for metal AM forging die fabrication • Estimated potential lead time savings for DLA forged parts • Estimated potential life-cycle cost savings. Project Description Currently, it is well established that metal AM is most suitable for the production of highly-engineered parts with complex geometry, low volume, prototype, custom parts, and parts made from expensive materials [4]. Forging dies fit these manufacturing requirements very well, since each forging die set is unique to a part or part family and most of the die materials are quite expensive. While forging dies are less complex than casting molds, they require superior mechanical properties for deforming metals inside the die cavity in a solid state. The following are the specific tasks anticipated for this project. Task 1: TRL and MRL Evaluation for Forging Die Additive Manufacturing Technology Readiness Level (TRL) and Manufacturing Readiness Level (MRL) for die fabrication using metal AM will be evaluated based on the guidelines set forth by NASA Technology Readiness

FIA MAGAZINE | AUGUST 2020 56